Anyone else work nightshift?

I'm a nightshift nurse so I usually take a nap before my shift, then sleep until 3-4pm afterwards. Since about 9 weeks pregnant no matter what I do, I can't get myself to sleep during the day anymore. Even though I'm exhausted I can't nap anymore. And after my shift I'm lucky if I'm able to sleep until noon. Not sure if a pregnancy can interfere with this type of thing. I'm luckily able to sleep fine at night on my days off. I'm so tired of this! Anyone else struggling with daytime sleep?